/*
 * Copyright (c) 2003-2013, KNOPFLERFISH project
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following
 * conditions are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above
 *   copyright notice, this list of conditions and the following
 *   disclaimer in the documentation and/or other materials
 *   provided with the distribution.
 *
 * - Neither the name of the KNOPFLERFISH project nor the names of its
 *   contributors may be used to endorse or promote products derived
 *   from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package org.knopflerfish.shared.cm;

import java.lang.reflect.Array;
import java.util.Dictionary;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Vector;

/**
 * Some utility methods for objects that implement Dictionary.
 *
 * @author Gatespace AB
 */

public final class DictionaryUtils {

  /**
   * Copy a dictionary.
   *
   * Deep copy where values aren't immutable. I.e.  Vector and arrays.
   *
   * @param in
   *            The Dictionary to create a copy of.
   * @return A copy of the Dictionary.
   */
  static public <K> Dictionary<K,Object> copyDictionary(Dictionary<K,Object> in) {
    if (in == null) {
      return null;
    }
    Hashtable<K, Object> out = new Hashtable<K, Object>();
    Enumeration<K> keys = in.keys();
    while (keys.hasMoreElements()) {
      K key = keys.nextElement();
      out.put(key, copyValue(in.get(key)));
    }
    return out;
  }

  /**
   * Recursive comparison of two dictionaries for equality.
   *
   * Equality is defined as <code>(o1 == null && 02 == null) ||
   * o1.equals(o2)</code>.
   *
   * @param first
   *            The first Dictionary to compare.
   * @param second
   *            The second Dictionary to compare.
   * @return true if both dictionaries are either null or recursively equal.
   */
  static public <K> boolean dictionariesAreEqual(Dictionary<K, Object> first,
                                                 Dictionary<K, Object> second)
  {
    if (bothAreNull(first, second))
      return true;
    if (onlyOneIsNull(first, second))
      return false;
    if (sizeIsNotEqual(first, second))
      return false;

    boolean result = true;
    Enumeration<K> keys = first.keys();
    while (result && keys.hasMoreElements()) {
      K key = keys.nextElement();
      Object v1 = first.get(key);
      Object v2 = second.get(key);
      result = valuesAreEqual(v1, v2);
    }
    return result;
  }

  static public <K> boolean dictionariesAreNotEqual(Dictionary<K, Object> first,
                                                    Dictionary<K, Object> second)
  {
    return !dictionariesAreEqual(first, second);
  }

  static private <V> V copyValue(V in) {
    if (in == null) {
      return null;
    }
    if (in.getClass().isArray()) {
      @SuppressWarnings("unchecked")
      V copy = (V) copyArray(in);
      return copy;
    } else if (in instanceof Vector) {
      Vector<?> v = (Vector<?>) in;
      @SuppressWarnings("unchecked")
      V copy = (V) copyVector(v);
      return copy;
    } else {
      return in;
    }
  }

  static private <V> Vector<V> copyVector(Vector<V> in) {
    if (in == null) {
      return null;
    }
    Vector<V> out = new Vector<V>();
    Enumeration<V> elements = in.elements();
    while (elements.hasMoreElements()) {
      out.addElement(copyValue(elements.nextElement()));
    }
    return out;
  }

  static private Object copyArray(Object in) {
    if (in == null) {
      return null;
    }
    int length = Array.getLength(in);
    Object out = Array
      .newInstance(in.getClass().getComponentType(), length);
    for (int i = 0; i < length; ++i) {
      Array.set(out, i, copyValue(Array.get(in, i)));
    }
    return out;
  }

  static private boolean valuesAreEqual(Object first, Object second)
  {
    if (bothAreNull(first, second))
      return true;
    if (onlyOneIsNull(first, second))
      return false;
    if (classesAreNotEqual(first, second))
      return false;

    if (first.getClass().isArray()) {
      return arraysAreEqual(first, second);
    } else if (first instanceof Vector) {
      return (second instanceof Vector)
             && vectorsAreEqual((Vector<?>) first, (Vector<?>) second);
    } else {
      return first.equals(second);
    }
  }

  static private boolean vectorsAreEqual(Vector<?> first, Vector<?> second) {
    if (bothAreNull(first, second))
      return true;
    if (onlyOneIsNull(first, second))
      return false;
    if (sizeIsNotEqual(first, second))
      return false;
    boolean result = true;
    for (int i = first.size(); result && i < first.size(); ++i) {
      result = valuesAreEqual(first.elementAt(i), second.elementAt(i));
    }
    return result;
  }

  static private boolean arraysAreEqual(Object first, Object second) {
    if (bothAreNull(first, second))
      return true;
    if (onlyOneIsNull(first, second))
      return false;
    if (lengthIsNotEqual(first, second))
      return false;
    int length = Array.getLength(first);
    boolean result = true;
    for (int i = 0; result && i < length; ++i) {
      result = valuesAreEqual(Array.get(first, i), Array.get(second, i));
    }
    return result;
  }

  static private boolean bothAreNull(Object first, Object second) {
    return first == null && second == null;
  }

  static private boolean onlyOneIsNull(Object first, Object second) {
    return !bothAreNull(first, second) && (first == null || second == null);
  }

  static private boolean sizeIsNotEqual(Dictionary<?, ?> first,
                                        Dictionary<?, ?> second)
  {
    return first.size() != second.size();
  }

  static private boolean sizeIsNotEqual(Vector<?> first, Vector<?> second)
  {
    return first.size() != second.size();
  }

  static private boolean lengthIsNotEqual(Object first, Object second) {
    return Array.getLength(first) != Array.getLength(second);
  }

  static private boolean classesAreNotEqual(Object first, Object second) {
    return !first.getClass().equals(second.getClass());
  }
}
